Conventionally, an atomizer which sprays a liquid in a container via a nozzle has been widely used in various fields. A known example of such an atomizer is an electrostatic atomizer which atomizes and sprays a liquid by Electro Hydrodynamics (EHD).
The electrostatic atomizer forms an electric field near a tip of a nozzle and uses the electric field to atomize and spray the liquid at the tip of the nozzle. Typically, the electrostatic atomizer is configured such that an electric field is formed between two electrodes (a pin and a capillary which correspond to the nozzle) by application of a voltage across the two electrodes (see, for example, Patent Literatures 1 and 2).
In carrying out desired atomization, it is important to control strength of an electric field formed near a tip of a nozzle. For example, in a case where the electric field is weak, atomization becomes unstable and the electrostatic atomizer itself is wetted due to spray-back (a phenomenon in which sprayed droplets come back to a device side). On the other hand, in a case where the electric field is stronger than necessary, multi-getting occurs.
A conventional electrostatic atomizer controls strength of an electric field formed near a tip of a nozzle, by directly adjusting a voltage to be applied across two electrodes. This method can be effectively used in a case where there is no factor, except a voltage, that influences the electric field. However, the method is ineffective in a case where there is a factor, in addition to a voltage, that influences the electric field.
As research advances, it is becoming clear that various factors, in addition to a voltage, influence the electric field. For example, it is becoming clear that a difference in design of each member constituting an electrostatic atomizer varies strength of an electric field formed near a tip of a nozzle. In such a case, it is necessary to directly compensate a voltage in consideration of an enormous number of parameters which vary in accordance with a design and the like of each member. However, it is difficult to detect all of the enormous number of parameters and directly compensate a voltage in accordance with values detected as the parameters.